With the development of modern science and technology, the number and types of electrical and electronic equipment continue to increase, so that the electromagnetic environment is increasingly complex. In this complex electromagnetic environment, how to reduce mutual electromagnetic harassment, so that the normal operation of various equipment, is an urgent problem; on the other hand, the poor electromagnetic environment will also have a negative impact on human beings and ecological.
With the development of electrical and electronic technology, the increasing popularity of household appliances and electronic products, radio and television, post and telecommunications communications and computer networks are increasingly developed, the electromagnetic environment is increasingly complex and deterioration of the electrical and electronic products, making the electromagnetic compatibility of electrical and electronic products (EMC electromagnetic interference EMI and electromagnetic anti-EMS) issues have been the increasing attention of the governments and production enterprises. Electronic and electrical products electromagnetic compatibility (EMC) is a very important quality indicators, it is not only related to the product itself, the reliability of the work and the use of safety, but also may affect the normal operation of other equipment and systems, the relationship between the protection of the electromagnetic environment.
In order to standardize the electromagnetic compatibility of electronic products, all developed countries and some developing countries have formulated electromagnetic compatibility standards. Electromagnetic compatibility standards are the basic requirements to enable products to work properly in the actual electromagnetic environment. The reason why they are called basic requirements means that even if the product meets the EMC standards, interference problems may occur in actual use. Most national standards are based on those developed by the International Electrotechnical Commission (IEC).
EMC includes two requirements: on the one hand, it refers to the equipment in the normal operation of the process of electromagnetic interference in the environment can not exceed a certain limit; on the other hand, it refers to the apparatus in the environment of the existence of electromagnetic interference with a certain degree of immunity, that is, electromagnetic sensitivity.
In recent years, with the high sensitivity of the electronic technology in the medical electrical equipment in a wide range of applications and new communication technologies, such as personal communication systems, cellular telephones, etc., in the rapid development of all areas of social life; medical electrical equipment not only emits electromagnetic energy itself, affecting radio broadcasting communication services and other equipment around the work, but also in the application of the environment in which it is also possible to be surrounded by such as communication equipment. Electromagnetic energy emission interference caused by the patient's injury.